Edge coating apparatus and coating method for photovoltaic cell sheets

The present application claims priority to Chinese Patent Application No. CN2021116769517, filed on Dec. 31, 2021, the entire content of which is incorporated herein by reference.

The present disclosure relates to the field of photovoltaic cell manufacturing, in particular to an edge coating apparatus and method for a photovoltaic cell precursor.

A crystalline silicon solar cell usually employs a metal electrode that formed by screen printing silver paste, and then high-temperature or low-temperature sintering, to lead out photon-generated carriers, which is also a most widely used metallization method for a crystalline silicon solar cell at present, and the metallization process is simple and also a mainstream mass production process at present. In recent years, as silicon precursor and cell processes are continuously developed, a production cost of the solar cell is continuously reduced, wherein a proportion of a cost of the expensive silver paste of a metallization production process in a whole cell cost is continuously increased, and a width-to-height ratio of a silver electrode is limited by the screen printing process, thereby hindering a further improvement of a cell efficiency.

In order to further reduce the cost of the solar cell and improve the cell efficiency, a possibility of mass production of the metal electrode of the solar cell that using an electroplating method is researched, wherein the electroplating method can employs cheaper metal, such as nickel, copper, or the like, to partially or completely replaced silver so as to reduce the cost.

In the crystalline silicon solar cell, different elements are doped to form an N-type diffusion layer and a P-type diffusion layer to form a cell PN junction, which generates a voltage difference, and carriers are generated under sunlight, to realize external power supply of the cell. In order to improve reliability of the solar cell, an edge of a cell precursor is required to be protected by an insulating material in the process of forming the metal electrode by an electroplating process, so as to prevent the metal from being deposited on the peripheral edge of the cell wafer. The insulating material can be selected from photo-curable ink, thermal-curable ink and insulating glue with a similar performance. The insulating material can be applied by non-contact coating; for example, CN201940332U discloses a non-contact edge coating device for a solar cell precursor, in which a precursor support is connected with a handling device, such that the precursor is moved into a groove of a roller to be coated with a coating material. However, the edge coating apparatus cannot meet a takt time required for mass production of the solar cell, and when a size tolerance of the silicon precursor is unavoidable, it is difficult to control the precision of covering during edge coating.

An object of the present disclosure is to provide an edge coating method for a photovoltaic cell precursor, so as to solve one or more problems in conventional art.

A first aspect of the disclosure provides an edge coating method for a photovoltaic cell precursor including:

In some embodiments, the step (2) includes:

In some embodiments, in the step (2-1), the precursor carrying platform is driven to rotate around a rotation center line extending in a vertical direction, to make the edge portion extend in the first direction.

In some embodiments, the step (2) further includes:

In some embodiments, during relative movement of the precursor carrying platform and the coating device along the first direction, a distance between the discharging portion of the coating device and the edge portion is kept at a constant preset value or within a preset range.

In some embodiments, a first chamfered portion and a second chamfered portion are formed at a front end and a rear end of the edge portion respectively, and the step (3) includes:

In some embodiments, in the step (3), the coating device is fixed and the precursor carrying platform is moved in the first direction.

In some embodiments, the coating device includes at least a coating wheel, and in the step (3), the coating wheel rotates around the rotation center line extending in the vertical direction for discharging, so as to coat the edge portion with the coating material.

In some embodiments, in the step (3), a velocity of relative horizontal movement of the precursor carrying platform and the coating wheel in the first direction is consistent with or as close as possible to a linear velocity of the coating wheel. Preferably, a ratio of the velocity of the relative horizontal movement of the precursor carrying platform and the coating wheel in the first direction to the linear velocity of the coating wheel is 0.5-1.2, such that coating materials with different viscosities can be adjusted within a certain range to achieve a same coating effect.

In some embodiments, the cell precursor has two edge portions provided oppositely and having parallel length extending directions, and in the step (3), during a process of relatively moving of the precursor carrying platform and the coating device, the two edge portions are coated by two coating devices provided on two sides of the cell precursor respectively.

In some embodiments, in the step (2), positions of the two coating devices are adjusted according to positions of the edge portions on the corresponding sides respectively.

In some embodiments, the cell precursor has two first edge portions oppositely provided and parallel to each other, and two second edge portions oppositely provided and parallel to each other, an angle between the first edge portion and the second edge portion is α, and the edge coating method includes the following step:

In some embodiments, the angle α between the first edge portion and the second edge portion is 90°.

In some embodiments, after coating of the first edge portions is completed, the cell precursor is transferred to another precursor carrying platform to realize coating of the second edge portions.

In some embodiments, the cell precursor has a plurality of edge portions, and after one of the edge portions is coated in the steps (2) and (3), the precursor carrying platform is rotated around the rotation center line extending in the vertical direction, and/or the coating device is moved, such that the position of the discharging portion of the coating device is correspondingly fitted with the position of another to-be-coated edge portion, and then the step (3) is repeated.

In some embodiments, the edge coating method further includes a curing step of transferring the cell precursor onto a carrying device after coating of all the edge portions of the cell precursor is completed, keeping all the edge portions in a suspended state, and curing the cell precursor.

In some embodiments, the coating material is liquid thermosetting resin or photo-curable acid-resistant resin soluble in an alkaline solution.

In some embodiments, a viscosity of the coating material is 50-1,200 cP, preferably 120-800 cP.

In some embodiments, the coating device includes a coating wheel, and the discharging portion is located at an outer circumference surface of the coating wheel; or, the coating device includes at least a coating spraying tube or a coating needle with a discharging opening, and the discharging opening forms the discharging portion.

Another aspect of the present disclosure provides an edge coating apparatus for a photovoltaic cell precursor, including a precursor carrying device and a coating device, wherein the precursor carrying device includes at least a precursor carrying platform for carrying the cell precursor, the coating device at least has a discharging portion, and the coating apparatus is configured to implement the edge coating method as described above.

Yet another aspect of the present disclosure provides an edge coating apparatus for a photovoltaic cell precursor including:

In some embodiments, the coating device includes a coating wheel capable of rotating around a rotation center line extending in a vertical direction for discharging, and a feeding mechanism for supplying a coating material to the coating wheel.

In some embodiments, the precursor carrying platform is a negative pressure sucking platform capable of sucking and fixing the cell precursor, the cell precursor has a to-be-coated edge portion, and when the cell precursor is placed on the precursor carrying platform, the edge portion is positioned on an outer side of the precursor carrying platform.

In some embodiments, an annular groove for accommodating the edge portion is provided in an outer circumference surface of the coating wheel, the coating wheel has an accommodating cavity for accommodating the coating material and discharging channels communicating the accommodating cavity and the annular groove, and the discharging channels are circumferentially spaced apart.

In some embodiments, the coating wheel includes an upper wheel body and a lower wheel body which are detachably connected, a plurality of upper slots circumferentially distributed at intervals are provided in an outer circumference surface of the upper wheel body, a plurality of lower slots circumferentially distributed at intervals are provided in an outer circumference surface of the lower wheel body, and the upper slots and the lower slots are fitted in a one-to-one correspondence manner and form the plurality of discharging channels.

In some embodiments, the precursor carrying platform is configured to rotate around the rotation center line extending in the vertical direction.

In some embodiments, the precursor carrying device further includes a platform adjusting mechanism for driving the precursor carrying platform to rotate around the rotation center line to adjust a position of the precursor carrying platform, the edge coating apparatus further includes a cell precursor positioning system for positioning an actual position of the cell precursor on the precursor carrying platform, and the cell precursor positioning system is in communication connection with the platform adjusting mechanism and the driving device.

In some embodiments, the coating device includes at least a coating spraying tube or a coating needle, the coating spraying tube or the coating needle has a discharging opening, and the discharging opening is oriented towards the precursor carrying platform.

In some embodiments, two coating devices are provided, and the two coating devices are arranged on two different sides of the precursor carrying platform in the first direction respectively.

In some embodiments, two or more precursor carrying devices are arranged at intervals along the first direction, and the edge coating apparatus further includes a handling device for transferring the cell precursor between different precursor carrying platforms.

In some embodiments, the edge coating apparatus further includes a holder for placing the coated cell precursor, an unloading device for transferring the cell precursor from the precursor carrying platform to the holder, and a curing system for curing the cell precursor, and the curing system is a hot air dryer or a photo-curing machine or a tunnel kiln.

Due to the application of the above technical solution, compared with the conventional art, the present disclosure has the following advantages:

In the drawings:—precursor carrying device;—precursor carrying platform;—negative pressure introduction mechanism;—coating device;—coating wheel;—upper wheel body;—lower wheel body;—annular groove;—discharging channel;—upper groove;—lower groove;—accommodating cavity;—material injection hole;

—feeding mechanism;—feeding pipe;—advancing device;—driving device;—cell precursor;—first edge portion;—second edge portion;—first chamfered portion;—second chamfered portion.

The technical solution of the present disclosure is further explained below in conjunction with the accompanying drawings and the preferred embodiments.

Referring to, an edge coating apparatus for a photovoltaic cell precursor includes a precursor carrying device, a coating device, an advancing deviceand a driving device, wherein, the precursor carrying deviceis horizontally movable along a first direction. The precursor carrying deviceat least includes a precursor carrying platformfor carrying a to-be-coated cell precursor, and the precursor carrying platformis rotatable around a rotation center line extending along a vertical direction. The advancing devicecan drive the precursor carrying deviceto integrally advance along the first direction. The coating deviceis horizontally movable in a second direction which is perpendicular to the first direction. For the first direction and the second direction, reference is made to schematic representation in.

In the present embodiment, the coating deviceincludes a coating wheelrotatable around the rotation center line extending in the vertical direction for discharging, and a feeding mechanismfor supplying a coating material to the coating wheel. An outer circumference surface of the coating wheelis provided with a discharging portion. The driving deviceis configured to drive the coating deviceto move in the second direction. In other embodiments, the coating devicemay also include a coating spraying tube or a coating needle with a discharging opening.

The precursor carrying platformis specifically a negative pressure sucking platform capable of sucking and fixing the cell precursor, and below which a negative pressure introduction mechanismis provided, such that the cell precursoris fixedly sucked after transferred onto the precursor carrying platformand synchronously moves with the movement of the precursor carrying platform.

The precursor carrying devicefurther includes a platform adjusting mechanism (not shown in the accompanying drawings) for driving the precursor carrying platformto rotate around the rotation center line to adjust a position of the precursor carrying platform, the platform adjusting mechanism may be specifically a motor provided below the precursor carrying platform, and the motor is configured to drive the precursor carrying platformto rotate around the rotation center line by a specified angle, so as to adjust a position of the cell precursoron the precursor carrying platform. When the cell precursoris supported on the precursor carrying platform, a to-be-coated edge portion thereof is positioned on an outer side of the precursor carrying platformto be fitted with the coating wheelwithout contact, such that the coating wheelcoats the edge portion of the cell precursorwith the coating material during rotation, so as to realize the coating of the edge portion.

The edge coating apparatus further includes a cell precursor positioning system (not shown in the accompanying drawings) for positioning an actual position of the cell precursoron the precursor carrying platform, the cell precursor positioning system at least includes a camera, the cell precursor positioning system is in communication connection with the platform adjusting mechanism and the driving device, and the platform adjusting mechanism drives the precursor carrying platformto rotate by a required rotation angle according to the actual position of the cell precursorpositioned by the cell precursor positioning system, such that a length extending direction of the to-be-coated edge portion is parallel to the first direction. The driving deviceis horizontally moved by a required distance along the second direction according to the actual position of the cell precursor, such that a position of the discharging portion of the coating wheelis correspondingly fitted with a position of the to-be-coated edge portion, and a tangential direction of the discharging portion is parallel to the length extending direction of the to-be-coated edge portion. Thus, the cell precursoris carried by the precursor carrying platform, and in the process that the whole precursor carrying deviceis horizontally moved along the first direction, different positions of the to-be-coated edge portion of the cell precursorsequentially pass through the discharging portion of the coating wheel, so as to realize the coating of the whole edge portion.

As shown in, the outer circumference surface of the coating wheelhas an annular groovefor accommodating the edge portion of the cell precursor, the coating wheelhas an accommodating cavityfor accommodating the coating material, and discharging channelscommunicating the accommodating cavityand the annular groove, and the plural discharging channelsare circumferentially spaced apart around the rotation center line of the coating wheel. Here, discharging openings of all the discharging channelsare provided at regular intervals on a circumferential side surface of the annular groove, such that as uniform discharging as possible can be realized when the coating wheelrotates. The discharging portion of the coating wheelis formed by one or more discharging openings of the coating wheelfacing the to-be-coated edge portion of the cell precursor, and the discharging openings of all the discharging channelsalternately form the discharging portion partially or completely during the rotation of the coating wheel. During the rotation of the coating wheel, the coating material in the accommodating cavityenters the annular groovethrough the plurality of discharging channelsby a centrifugal force, and the edge portion of the cell precursorpasses through the annular grooveand receives the coating material in the annular grooveduring the horizontal movement of the cell precursorin the first direction, so as to realize coating.

Specifically, the coating wheelincludes an upper wheel bodyand a lower wheel bodywhich are detachably connected, a plurality of upper slotswhich are circumferentially distributed at intervals are provided in an outer circumference surface of the upper wheel body, a plurality of lower slotswhich are circumferentially distributed at intervals are provided in an outer circumference surface of the lower wheel body, and when the upper wheel bodyand the lower wheel bodyare fixedly fitted with each other to form the coating wheel, the upper slotsand the lower slotsare correspondingly fitted with each other to form the plurality of discharging channels. Thus, not only the manufacture of the upper wheel bodyand the lower wheel bodyis simpler, but also an interior of the coating wheeland the discharging channelcan be cleaned conveniently, and residues caused by the fact that the coating material is not easy to clean after dried are avoided. An extending direction of the discharging channelis not limited herein, and the discharging channel may extend along a radial direction of the coating wheelas shown in the present embodiment, and may also extend along a vortex curve in other embodiments, such that the coating material in the accommodating cavitycan flow outwards into the annular grooveunder the action of the centrifugal force when the coating wheelrotates.

An upper portion of the coating wheel, specifically the upper wheel body, is further provided with a material injection holethrough in an up-down direction, the feeding mechanismat least has a feeding pipe, a lower portion of the feeding pipeis inserted into the material injection holein a sealing fit manner and is rotatable relative to the upper wheel body, and in the process that the coating wheelrotates around an axis thereof to coat the edge portion of the cell precursor, the feeding pipeis kept stationary and continuously supplies the coating material into the accommodating cavityof the coating wheel. Furthermore, when the coating wheelis required to be cleaned, a cleaning material can be injected into the accommodating cavityof the coating wheelby the feeding mechanism, so as to automatically clean the accommodating cavity, the discharging channeland the annular grooveof the coating wheel, and the cleaning is also quite convenient.

The coating material is specifically liquid thermosetting resin or photo-curable acid-resistant resin soluble in an alkaline solution, and has a viscosity of 50-1,200 cP, preferably 120-800 cP.